gistfile1.txt

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
int chday(int day,int month,int year);
int chmonth(int month);
int chyear(int year);
int leapYear(int y);
int day_of_year(int d,int m,int y);

int chday(int day,int month,int year) {
	if(month==1 && month==3 && month==5 && month==7 && month==9 && month==11){
	 while (day < 1 && day > 31) {
        return printf("H timh gia thn hmera den einai swsth");
        scanf("%d", &day);
		}
		} 
		 else{ return printf("H timh gia thn hmera einai swsth");
	   }
	   
	   

	if(month==2 && (year%400==0)||((year%4==0)&&(year%100!=0)))
	{
			while (day < 1 && day > 29)
			{
			return printf("H timh gia thn hmera den einai swsth");
			scanf("%d", &day);
			}
			
		}
		else {
		return printf("H timh gia thn hmera einai swsth");
		}
	
	
	if(month==2){
	 while (day < 1 && day > 28) {
        return printf("H timh gia thn hmera den einai swsth");
        scanf("%d", &day);
        
		}
        
		}
		else{
		return("H timh gia thn hmera einai swsth");
			
		}
        

	
	
	
    while (day < 1 && day > 30) {
        return printf("H timh gia thn hmera den einai swsth");
        scanf("%d", &day);
        
		}
        return("H timh gia thn hmera einai swsth");
    }



int chmonth(int month) {
    while (month < 1 && month > 12) {
        return printf("H timh gia ton mhna den einai swsth");
        scanf("%d", &month);
    }

    return printf("H timh gia thn hmera einai swsth");
}

int chyear(int year) {
    while(year < 0) {
        return printf("H timh gia ton xrono den einai swsth");
        scanf("%d", &year);
    }

    return printf("h timh gia ton xrono einai swsth");
}
int leapYear(int y)//ÏÍÏÌÁ ÓÕÍÁÑÔÇÓÇÓ
{
    if((y%400==0)||((y%4==0)&&(y%100!=0)))
        //Ýíá äßóåêôï Ýôïò åéíáé áñôéá äéáéñåôáéï ìå ôï 400
        //åíá äéóôåêôï åôïò åéíáé áñôéá ðïëëáðëáóóéï ìå ôï 4
        //áëëá áí ï÷é äéáéñåôáéï äéáéñåôáéï ìå ôï 100
       return printf("To etos einai disekto");
    else//all other years are not leap year
        return printf("To etos den einai disekto");
}
int day_of_year(int d,int m,int y){
	int s,l;
	s=m*d;//áõôïò åéíáé ï áõîïíôáò áñéèìïò
	l=365-s;//áõôåò åéíáé ïé ìåñåò ðïõ õðïëõðïíôáé
	return printf("O afksontas arithmou einai %d kai oi meres pou upolupontai einai %d",s,l);
}

int main(int argc, char *argv[])
 {
    // declaring variables
    int day, month, year;

    // input for day
    printf("Dwse mera tou xronou: ");
    scanf("%d", &day);

    // input for month
    printf("Dwse mhna tou xronou: ");
    scanf("%d", &month);

    // input for year
    printf("Dwse xrono: ");
    scanf("%d", &year);
    struct hmeromhnia{
    	int day;
    	int month;
    	int year;
	};
	chday(day,month,year);
	chmonth(month);
	chyear(year);
	leapYear(year);
	day_of_year(day,month,year);

    return 0;
}